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ANS Student Conference 2025
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General Kenneth Nichols and the Manhattan Project
Nichols
The Oak Ridger has published the latest in a series of articles about General Kenneth D. Nichols, the Manhattan Project, and the 1954 Atomic Energy Act. The series has been produced by Nichols’ grandniece Barbara Rogers Scollin and Oak Ridge (Tenn.) city historian David Ray Smith. Gen. Nichols (1907–2000) was the district engineer for the Manhattan Engineer District during the Manhattan Project.
As Smith and Scollin explain, Nichols “had supervision of the research and development connected with, and the design, construction, and operation of, all plants required to produce plutonium-239 and uranium-235, including the construction of the towns of Oak Ridge, Tennessee, and Richland, Washington. The responsibility of his position was massive as he oversaw a workforce of both military and civilian personnel of approximately 125,000; his Oak Ridge office became the center of the wartime atomic energy’s activities.”
D. J. Euh, B. G. Huh, B. J. Yun, C.-H. Song, I. G. Kim
Nuclear Technology | Volume 164 | Number 3 | December 2008 | Pages 368-384
Technical Paper | Thermal Hydraulics | doi.org/10.13182/NT164-368
Articles are hosted by Taylor and Francis Online.
The reflood rate in a core is an important parameter for core cooling during a large-break loss-of-coolant-accident (LBLOCA) reflood period, and it strongly depends on the thermal-hydraulic conditions in the downcomer. During this period, downcomer boiling has an important influence on the transient behavior of a postulated LBLOCA because it can degrade the hydraulic head in a downcomer and consequently affect the reflood flow rate for core cooling. Although it is recognized that downcomer boiling is critical to correctly predict the reflood phenomena of an LBLOCA transient, especially for a direct vessel injection adapted system like the advanced power reactor APR1400, the amount of experimental data and code assessment in this area is relatively limited. To improve the state of knowledge relative to downcomer boiling, a test program at the Downcomer Boiling (DOBO) facility is progressing for the reflood phase of a postulated LBLOCA. The DOBO facility was designed to meet a full scale for the height and gap of a reactor downcomer. The DOBO test revealed a strong multidimensional boiling behavior, which induces the need for performance evaluation of the best-estimate codes that are used to analyze a nuclear reactor's thermal-hydraulic safety, since they have mostly been used for one-dimensional system behavior. In this study, RELAP, MARS, and TRACE are evaluated by using measured two-phase-flow data. Based on the assessments, the modeling capability and weak points of the safety analysis codes are addressed for multidimensional downcomer boiling phenomena. Two models for a downcomer are considered to assess the codes for the DOBO tests, which are also applied to a plant analysis.
